Former Sen. Rick Santorum (R-Pa.) threw his support behind state Attorney General Jon Bruning's (R) primary bid for the open Nebraska Senate seat today.

The endorsement marks the former presidential candidate's first foray into Congressional politics since dropping out of the national race in April, and it puts him at odds with some conservatives and tea party champions in Washington, D.C. — including Sen. Jim DeMint (R-S.C.) — who have backed state Treasurer Don Stenberg.

Bruning faces a competitive primary with Stenberg and state Sen. Deb Fischer on May 15. But Republicans consider Bruning to be the frontrunner for the nomination against former Sen. Bob Kerrey (D-Neb.) this fall. It's worth noting that Santorum might not have fond memories of Kerrey. A few weeks into his Senate career, Kerrey delivered this zinger about him: "Santorum is Latin for asshole."

In a statement, Santorum praised Bruning, calling him "the strongest conservative candidate to defeat Bob Kerrey in November and help Republicans take back the Senate."

"Jon Bruning is a trusted conservative who is unapologetically pro-life, will fight to reduce the size of the federal government and will ensure that the government spends less and does not tax more," Santorum said.

Santorum's backing also comes one day before he's scheduled to meet with former Massachusetts Gov. Mitt Romney, the presumptive GOP nominee for president, in his hometown of Pittsburgh.